Low molecular weight polyethylene polyamines are used in a wide variety of applications such as corrosion inhibitors, fabric softeners, lubricating oil additives, fungicides and many others. Despite the utility of polyethylene polyamines, they are currently obtained only as by-products of ethylenediamine manufactured by the reaction of ethylene dichloride with excess ammonia. Since the polyamines are by-products of ethylenediamine preparation, the supply and quality of available polyethylene polyamines are often variable. Moreover, since sodium chloride is co-produced in large quantities, separation of the products from the sodium chloride and the handling and disposal of this corrosive inorganic salt require special measures.
The prior art discloses various attempts to circumvent these difficulties and to provide controllable, efficient routes to polyethylene polyamines:
U.S. Pat. No. 4,036,881 discloses the preparation of polyalkylene polyamines by reacting an alkanolamine with an alkyleneamine compound in the presence of a phosphorus containing substance selected from the group consisting of acidic metal phosphates, phosphoric acid compounds and anhydrides and the phosphate esters.
U.S. Pat. No. 4,044,053 is somewhat similar to the '881 patent except that the alkyleneamine compound is present in an excess amount and a diol is used in place of the alkanolamine.
U.S. Pat. No. 4,324,917 discloses ion exchange resins containing phosphonic acid functionality as catalysts for production of polyethylene polyamines by alkylation of alkyleneamines such as ethylenediamine with alkanolamines such as monoethanolamine.
U.S. Pat. No. 4,314,083 discloses a process for selectively preparing predominantly noncyclic polyalkylene polyamines by reacting an alkanolamine with an alkyleneamine compound in the presence of a salt of a nitrogen or sulfur containing substance or the corresponding acid.
U.S. Pat. No. 3,714,259 discloses the preparation of linear polyethylene amines by contacting ethanolamine with ethylenediamine compound in the presence of hydrogen and a hydrogenation catalyst. An example of a hydrogenation catalyst is nickel containing copper and chromium components. Significant amounts of water are included in the feedstock, mainly 25 to 50 wt % based on the combined starting ethylenediamine and monoethanolamine.
U.S. Pat. No. 3,766,184 discloses the reductive amination of monoethanolamine by metallic catalysts of iron and nickel and/or cobalt in the presence of hydrogen.
The prior art requires a source of preformed ethylenediamine for reaction with monoethanolamine to produce polyethylene amines. The production of ethylenediamine is an additional process step which extends and complicates the prior art routes to polyethylene amines. Thus, production of polyethylene amines requires preparation of substantial quantities of both monoethanolamine, the alkylating agent, and ethylenediamine, the aminating agent, in separate steps and subsequent copolymerization of the monomers to provide polyethylene amines. Prior art routes to polyethylene polyamines are therefore limited by their dependency on a sufficient supply of preformed ethylenediamine in the reactions.